U.S. patent application number 15/595029 was filed with the patent office on 2018-01-11 for image forming apparatus.
This patent application is currently assigned to KYOCERA Document Solutions Inc.. The applicant listed for this patent is KYOCERA Document Solutions Inc.. Invention is credited to Okito OGASAHARA.
Application Number | 20180011421 15/595029 |
Document ID | / |
Family ID | 60812798 |
Filed Date | 2018-01-11 |
United States Patent
Application |
20180011421 |
Kind Code |
A1 |
OGASAHARA; Okito |
January 11, 2018 |
IMAGE FORMING APPARATUS
Abstract
An image forming apparatus includes a developer container, a
development device, a developer replenishment device and a control
part. The control part obtains a replenishment amount (X) of the
developer replenished by the developer replenishment device from a
last-time replenishment until a this-time replenishment and a
predicted consumption (Y) of the developer, calculated based on the
image data output from the last-time replenishment until the
this-time replenishment, and informs abnormality when an absolute
value of a difference of the replenishment amount (X) and the
predicted consumption (Y) is larger than a threshold value.
Inventors: |
OGASAHARA; Okito;
(Osaka-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KYOCERA Document Solutions Inc. |
Osaka |
|
JP |
|
|
Assignee: |
KYOCERA Document Solutions
Inc.
Osaka
JP
|
Family ID: |
60812798 |
Appl. No.: |
15/595029 |
Filed: |
May 15, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G03G 15/0856 20130101;
G03G 15/556 20130101; G03G 15/0849 20130101; G03G 21/1814 20130101;
G03G 15/0877 20130101; G03G 15/0879 20130101 |
International
Class: |
G03G 15/08 20060101
G03G015/08; G03G 21/18 20060101 G03G021/18 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 6, 2016 |
JP |
2016-134201 |
Claims
1. An image forming apparatus comprising: a developer container
configured to contain a developer; a development device configured
to develop an electrostatic latent image into a toner image using
the developer, the electrostatic latent image being formed on an
image carrier based on image data; a developer replenishment device
configured to replenish the developer from the developer container
to the development device; and a control part configured to obtain
a replenishment amount (X) of the developer replenished by the
developer replenishment device from a last-time replenishment until
a this-time replenishment and a predicted consumption (Y)
calculated based on the image data output from the last-time
replenishment until the this-time replenishment, and to inform
abnormality when an absolute value (|X-Y|) of a difference (X-Y) of
the replenishment amount (X) and the predicted consumption (Y) is
larger than a threshold value.
2. The image forming apparatus according to claim 1, wherein the
control part controls the developer replenishment device so as to
replenish the developer to the development device from the
developer container when the absolute value (|X-Y|) of the
difference (X-Y) of the replenishment amount (X) and the predicted
consumption (Y) is equal to or smaller than the threshold value and
the difference (X-Y) of the replenishment amount (X) and the
predicted consumption (Y) is negative.
3. The image forming apparatus according to claim 2, wherein the
control part informs abnormality when a number of times that it is
decided that the absolute value (|X-Y|) of the difference (X-Y) of
the replenishment amount (X) and the predicted consumption (Y) is
larger than the threshold value reaches a predetermined number of
time.
4. An image forming apparatus comprising: a developer container
configured to contain a developer; a development device configured
to develop an electrostatic latent image into a toner image using
the developer, the electrostatic latent image being formed on an
image carrier based on image data; a developer replenishment device
configured to replenish the developer from the developer container
to the development device; a transferring device configured to
transfer the toner image developed by the development device to a
medium; a collecting device configured to collect the developer
remained on the image carrier after the toner image is transferred
to the medium by the transferring device; and a control part
configured to obtain a replenishment amount (X) of the developer
replenished by the developer replenishment device from a last-time
replenishment until a this-time replenishment, a predicted
consumption (Y) of the developer, calculated based on the image
data output from the last-time replenishment until the this-time
replenishment and a collected amount (Z) of the developer collected
by the collecting device from the last-time replenishment until the
this-time replenishment, and to inform abnormality when an absolute
value (|X-(Y+Z)|) of a difference (X-(Y+Z)) of the replenishment
amount (X) and a sum (Y+Z) of the predicted consumption (Y) and the
collected amount (Z) is equal to or larger than a threshold
value.
5. The image forming apparatus according to claim 4, wherein the
control part controls the developer replenishment device so as to
replenish the developer to the development device from the
developer container when the absolute value (|X-(Y+Z)|) of the
difference (X-(Y+Z)) of the replenishment amount (X) and the sum
(Y+Z) of the predicted consumption (Y) and the collected amount (Z)
is equal to or smaller than the threshold value and a difference
(X-(Y+Z)) of the replenishment amount (X) and the sum (Y+Z) of the
predicted consumption (Y) and the collected amount (Z) is
negative.
6. The image forming apparatus according to claim 1, wherein the
predicted consumption (Y) is varied for a solid pattern and a line
pattern of the image data.
Description
INCORPORATION BY REFERENCE
[0001] This application is based on and claims the benefit of
priority from Japanese Patent application No. 2016-134201 filed on
Jul. 6, 2016, which is incorporated by reference in its
entirety.
BACKGROUND
[0002] The present disclosure relates to an image forming apparatus
which forms an image on a sheet.
[0003] In an electrophotographic type image forming apparatus, when
an abnormality such as a decreasing in density of a formed image
and a scattering of a toner, is detected, countermeasures
corresponding to the abnormality are taken. For example, a refresh
operation in which a developer carried on a developer carrier is
once discharged is carried out. Alternatively, a requirement for
cleaning work by a service man is informed. Conventionally, such an
abnormality is detected by an optical sensor detecting a scattered
toner or a density of a formed image. For accurate detection, it is
required to provide the optical sensor at a plurality of positions
or to clean the optical sensor itself. This causes increasing in
cost. Accordingly, it is desirable to detect such an abnormality
without using the optical sensor as much as possible.
[0004] On the other hand, there is an image forming apparatus
configured such that a toner consumption is calculated using an
increasing degree of density of a toner image on an image carrier
for a difference between a toner replenishment amount and a toner
replenishment amount and then a toner replenishment amount is
adjusted based on the calculated toner consumption.
[0005] In the image forming apparatus, the density of the toner
imager on the image carrier is detected by a reflection type
optical sensor. In this case, because a transferring rate of the
toner to the image carrier is not 100% and the toner is overlapped
on the image carrier, the toner consumption cannot be accurately
detected using the density detected by the reflection type image
sensor. In addition, if the image carrier such an intermediate
transferring belt is damaged, an accurate density cannot be
detected.
SUMMARY
[0006] In accordance with an aspect of the present disclosure, an
image forming apparatus includes a developer container, a
development device, a developer replenishment device and control
part. The developer container is configured to contain a developer.
The development device is configured to develop an electrostatic
latent image into a toner image using the developer. The
electrostatic latent image is formed on an image carrier based on
image data. The developer replenishment device is configured to
replenish the developer from the developer container to the
development device. The control part is configured to obtain a
replenishment amount (X) of the developer replenished by the
developer replenishment device from a last-time replenishment until
a this-time replenishment and a predicted consumption (Y) of the
developer, calculated based on the image data output from the
last-time replenishment until the this-time replenishment, and to
inform abnormality when an absolute value (|X-Y|) of a difference
(X-Y) of the replenishment amount (X) and the predicted consumption
(Y) is larger than a threshold value.
[0007] In accordance with another aspect of the present disclosure,
an image forming apparatus includes a developer container, a
development device, a developer replenishment device, a
transferring device, a collecting device and a control part. The
developer container is configured to contain a developer. The
development device is configured to develop an electrostatic latent
image into a toner image using the developer. The electrostatic
latent image is formed on an image carrier based on image data. The
developer replenishment device is configured to replenish the
developer from the developer container to the development device.
The transferring device is configured to transfer the toner image
developed by the development device to a medium. The collecting
device is configured to collect the developer remained on the image
carrier after the toner image is transferred to the medium by the
transferring device. The control part is configured to obtain a
replenishment amount (X) of the developer replenished by the
developer replenishment device from a last-time replenishment until
a this-time replenishment, a predicted consumption (Y) of the
developer, calculated based on the image data output from the
last-time replenishment until the this-time replenishment and a
collected amount (Z) of the developer collected by the collecting
device from the last-time replenishment until the this-time
replenishment, and to inform abnormality when an absolute value
(|X-(Y+Z)|) of a difference (X-(Y+Z)) of the replenishment amount
(X) and a sum (Y+Z) of the predicted consumption (Y) and the
collected amount (Z) is equal to or larger than a threshold
value.
[0008] The above and other objects, features, and advantages of the
present disclosure will become more apparent from the following
description when taken in conjunction with the accompanying
drawings in which a preferred embodiment of the present disclosure
is shown by way of illustrative example.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a view schematically showing an image forming
apparatus according to an embodiment of the present disclosure.
[0010] FIG. 2 is a side view showing an image forming part in the
image forming apparatus according to the embodiment of the present
disclosure.
[0011] FIG. 3 is a side view showing a toner replenishment path in
the image forming apparatus according to the embodiment of the
present disclosure.
[0012] FIG. 4 is a side view showing a toner collection device in
the image forming apparatus according to an embodiment of the
present disclosure.
[0013] FIG. 5 is a block diagram showing a control part in the
image forming apparatus according to the embodiment of the present
disclosure.
[0014] FIG. 6 is a flowchart explaining an abnormality detecting
process of a first embodiment, in the image forming apparatus
according to the embodiment of the present disclosure.
[0015] FIG. 7 is a flowchart explaining an abnormality detecting
process of a second embodiment, in the image forming apparatus
according to the embodiment of the present disclosure.
[0016] FIG. 8 is a flowchart explaining an abnormality detecting
process of a third embodiment, in the image forming apparatus
according to the embodiment of the present disclosure.
DETAILED DESCRIPTION
[0017] Hereinafter, with reference to the attached drawings, an
image forming apparatus according to an embodiment of the present
disclosure will be described.
[0018] With reference to FIG. 1, the image forming apparatus
according to an embodiment of the present disclosure will be
described. FIG. 1 is a sectional view showing a structure of the
image forming apparatus. The image forming apparatus 100 is a
quadruple tandem type color printer including four image forming
parts Pa, Pb, Pc and Pd which are adjacently arranged and forma
full color image. The four image forming parts Pa, Pb, Pc and Pd
respectively correspond to four different colors (magenta, cyan,
yellow and black). In the following description, a near side of a
paper plan of FIG. 1 shows a front side of the image forming
apparatus 1, and left and right directions are based on a direction
in which the image forming apparatus is seen from the front
side.
[0019] In an apparatus main body of the image forming apparatus
100, the four image forming parts Pa to Pd are adjacently arranged
in the order from the right side of FIG. 1. These image forming
parts Pa to Pd respectively form images of magenta, cyan, yellow
and black.
[0020] In these image forming parts Pa to Pd, photosensitive drums
1a, 1b, 1c and 1d are respectively provided so as to be rotatable
in the counterclockwise direction in FIG. 1. The photosensitive
drums 1a to 1d are examples of image carries each of which carries
a visible image (a toner image) of each color. Above the
photosensitive drums 1a to 1d, an intermediate transferring belt 8
is supported between a driven roller 10 and a driving roller 11 so
as to circulate. The intermediate transferring belt 8 is an example
of an image carrier which carries a visible image (a toner image)
formed by overlapping the visible image of each color and a medium
to which the toner image is transferred. In an inner hollow space
of the intermediate transferring belt 8, first transferring rollers
6a, 6b, 6c and 6d are rotatably supported so as to oppose to the
photosensitive drums 1a to 1d via the intermediate transferring
belt 8. The first transferring rollers 6a, 6b, 6c and 6d are
examples of transferring device which transfer the toner images
from the photosensitive drums 1a to 1d to the intermediate
transferring belt 8. At the left side of the driving roller 11, a
secondary transferring roller 9 is rotatably supported so as to
oppose to the driving roller 11 via the intermediate transferring
belt 8. The second transferring roller 9 is an example of a
transferring device which transfers the toner image from the
intermediate transferring belt 8 to a sheet. The sheet is an
example of a medium on which the toner image is transferred.
[0021] On a downstream side of the secondary transferring roller 9
in a rotation direction of the intermediate transferring belt 8
(near the driven roller 10 in this embodiment), a belt cleaning
device 19 is disposed. The belt cleaning device 19 removes the
toner and the others remained on a surface of the intermediate
transferring belt 8. The belt cleaning device 19 is an example of a
collection device which collects the toner remained on the
intermediate transferring belt 8 after the toner image is
transferred to the sheet. The belt cleaning device 19 has a blade
and a collection part. The blade comes into contact with the
intermediate transferring belt 8 from a counter direction to the
rotation direction of the intermediate transferring belt 8. The
toner removed by the blade is collected in the collection part. The
toner collected in the collection part is conveyed toward the front
side of the image forming apparatus 100 by a collection spiral. On
a front face of the collection part, a discharge port through which
the conveyed toner is discharged is formed.
[0022] The sheet P on which the toner image is to be transferred is
stored in a sheet feeding cassette 16 provided in a lower portion
of the apparatus main body. The sheet P is conveyed to the
secondary transferring roller 9 via a feed roller 12a and a
registration roller pair 12b.
[0023] Next, the image forming parts Pa to Pd will be described. In
the image forming parts Pa to Pd, charging devices 2a, 2b, 2c and
2d, developing devices 3a, 3b, 3c and 3d and drum cleaning devices
7a, 7b, 7c and 7d are respectively disposed around the
photosensitive drums 1a to 1d. The charging devices 2a to 2d charge
the photosensitive drums 1a to 1d respectively. The developing
devices 3a to 3d develop electrostatic latent images formed on the
photosensitive drums 1a to 1d with the toner respectively. The drum
cleaning devices 7a to 7d remove and collect the developer (the
toner) remained on the photosensitive drums 1a to 1d respectively
after the toner images are transferred. Below the image forming
parts Pa to Pd, an exposing unit 5 is disposed. The exposing unit 5
performs exposing to the photosensitive drums 1a to 1d according to
an image data.
[0024] Next, an image forming operation will be described. When the
image data is input from an image input device such as a personal
computer, the charging devices 2a to 2d respectively charge the
surfaces of the photosensitive drums 1a to 1d uniformly, and then
the exposing unit 5 performs the exposing to the photosensitive
drums 1a to 1d according to the input image data to form
electrostatic latent images corresponding to the input image data
on the photosensitive drums 1a to 1d. The electrostatic latent
images are developed by the developing devices 3a to 3d into toner
images of corresponding colors. Then, by applying a predetermined
transferring voltage between the first transferring rollers 6a to
6d and the photosensitive drums 1a to 1d, the toner images of
magenta, cyan, yellow and black colors are first-transferred on the
intermediate transferring belt 8. After that, in order to prepare
for formation of next new electrostatic latent images on the
photosensitive drums 1a to 1d, the toner remained on the surfaces
of the photosensitive drums 1a to 1d are removed by the drum
cleaning devices 7a to 7d respectively. If a ratio of the toner to
the two component developer filled in each of the developing
devices 3a to 3d is lower than a predetermined value by the image
forming operation described later, the toner is supplied to the
developing devices 3a to 3d from toner containers 4a to 4d as
developer containers respectively.
[0025] The toner images formed on the photosensitive drums 1a to 1d
are sequentially transferred on the intermediate transferring belt
8 and then a full color toner image is secondary-transferred on the
sheet P by the secondary transferring roller 9. The full color
toner image is heated and pressed at a fixing device 13 to be fixed
on the sheet P. The sheet P on which the full color toner image has
been fixed is ejected by an ejection roller pair 15 on the ejection
tray 7.
[0026] Next, with reference to FIG. 2, the image forming part Pa
described above will be described in detail. FIG. 2 is a partial
view showing the image forming part. The image forming parts Pb to
Pd each have the substantially same structure as the image forming
part Pa, and their detail descriptions are omitted. Around the
photosensitive drum 1a, the charging device 2a, the developing
device 3a, the first transferring roller 6a and the cleaning device
7a described above are arranged along the rotation direction of the
photosensitive drum 1a (the counterclockwise direction in FIG.
2).
[0027] The charging device 2a has a charging roller 20 and a
charging cleaning roller 21. The charging roller 20 comes in
contact with the surface of the photosensitive drum 1a and applies
a charging voltage on the photosensitive drum 1a. The charging
cleaning roller 21 cleans the charging roller 20.
[0028] The developing device 3a has a developer container 30 in
which the two component developer containing a magnetic carrier and
a toner is contained. In a lower portion of the developer container
30, an agitating/conveying chamber 31 and a supplying/conveying
chamber 32 are formed. The agitating/conveying chamber 31 has a
toner replenishment port 37 through which the toner replenished
from the toner container 4a by a toner replenishment device 40 (a
developer replenishment device, refer to FIG. 3) is received. In
the agitating/conveying chamber 31 and the supplying/conveying
chamber 32, an agitating/conveying screw 33a and a
supplying/conveying screw 33b are rotatably disposed respectively.
The agitating/conveying screw 33a and the supplying/conveying screw
33b mix the toner replenished with the magnetic carrier, agitate
them and charge the toner. The developer container 30 is provided
with a toner concentration sensor 38 which detects an amount of the
toner contained in the developer container 30. When the toner
concentration sensor 38 detects that an amount of the toner in the
developer container 30 is smaller than a predetermined value, the
toner replenishment device 40 described later replenishes the toner
from the toner container 4a to the developer container 30. As the
toner concentration sensor 38, a magnetic permeability sensor may
be used.
[0029] The developer container 30 has an opening 30a formed at a
portion opposing to the photosensitive drum 1a. In the developer
container 30, a magnetic roller 34 and a development roller 35 are
disposed. The magnetic roller 34 is positioned above the
supplying/conveying screw 33b so as to opposite to the
supplying/conveying screw 33b. The development roller 35 is
positioned at the left upper oblique side of the magnetic roller 34
so as to opposite to the magnetic roller 34. Apart of an outer
circumferential face of the development roller 35 is exposed
through the opening 30a and opposes to the photosensitive drum 1a.
The magnetic roller 34 and the development roller 35 are rotated in
the clockwise direction in FIG. 2.
[0030] On an upstream side of the opposing area R of the
development roller 35 and the magnetic roller 34 in a rotation
direction of the magnetic roller 34, a regulating blade 36 is
attached along a length direction of the magnetic roller 34 (a
perpendicular direction to the paper plan of FIG. 2). Between a tip
edge of the regulating blade 36 and an outer circumferential face
of the magnetic roller 34, a small gap is formed.
[0031] The developer is agitated while circulating between the
agitating/conveying chamber 31 and the supplying/conveying chamber
32 in the developer container 30 by the agitating/conveying screw
33a and the supplying/conveying screw 33b. This charges the toner.
The developer containing the charged toner is conveyed to the
magnetic roller 34 by the supplying/conveying screw 33b to form a
magnetic brush around the magnetic roller 34. A thickness of the
magnetic brush is regulated by the regulating blade 36. The
magnetic brush of which the thickness has been regulated is
conveyed to the opposing area R of the magnetic roller 34 and the
development roller 35. At the opposing area R, the magnetic brush
forms a toner layer on the development roller 35 by voltage
difference between a DC voltage applied to the magnetic roller 34
and a DC voltage applied to the development roller 35 and magnetic
field generated by the magnetic roller 34.
[0032] The toner layer formed on the development roller 35 is
conveyed by the rotation of the development roller 35 to the
opposing area where the photosensitive drum 1a and the development
roller 35 are opposite to each other. Because the predetermined
voltage is applied to the development roller 35, the toner fries
from the development roller 35 to the photosensitive drum 1a owing
to voltage difference between the development roller 35 and the
photosensitive drum 1a, and develops the electrostatic latent image
on the photosensitive drum 1a.
[0033] The drum cleaning device 7a has a rubbing roller 22, a
cleaning blade 23 and a collection spiral 24. The drum cleaning
device 7a is an example of a collection device which collects the
toner remained on the photosensitive drum 1 after the toner image
is transferred to the intermediate transferring belt 8.
[0034] The rubbing roller 22 comes into pressure contact with the
photosensitive drum 1a at a predetermined pressure. The cleaning
blade 23 is supported on a downstream side of the contact portion
of the rubbing roller 22 and the photosensitive drum 1a in the
rotation direction of the photosensitive drum 1a, and comes in
contact with the photosensitive drum 1a from a counter direction to
the rotation direction of the photosensitive drum 1a. The
collection spiral 24 conveys the toner removed from the surface of
the photosensitive drum 1a by the rubbing roller 22 and the
cleaning blade 23 to the front side of the image forming apparatus
100. On a front face of the drum cleaning device 7a, a discharge
port through which the conveyed toner is discharged is formed.
[0035] Next, with reference to FIG. 3, the toner replenishment
device 40 will be described. The toner replenishment device 40
replenishes the toner from the toner container 4a to the developer
container 30 of the development device 3a. FIG. 3 is a view
schematically showing a toner replenishment path.
[0036] As shown in FIG. 3, the toner replenishment device 40
includes a toner conveying duct 41, a conveying screw 42, a toner
replenishment duct 43 and a shutter member 44. The toner conveying
duct 4l extends horizontally from a lower portion of the toner
container 4a. The conveying screw 42 is disposed in the toner
conveying duct 41. The toner replenishment duct 43 is communicated
with the toner conveying duct 41 and extend in the vertical
direction to communicate with the toner replenishment port 37 of
the development device 3a. The shutter member 44 is slidable
horizontally to open and close the toner replenishment port 37 of
the development device 3a.
[0037] On one end of the toner conveying duct 41, a toner receiving
port 40a is formed. The toner receiving port 40a is communicated
with the toner container 4a. On the other end of the toner
conveying duct 41, a toner discharge port 40b is formed. The toner
discharge port 40b is communicated with the toner replenishment
duct 43.
[0038] The toner conveying screw 42 is disposed in the toner
conveying duct 41 so as to be rotatable. To an end of the toner
conveying screw 42, a replenishment motor M is coupled. When the
replenishment motor M is driven, the conveying screw 42 is rotated
to convey the toner received into the toner conveying duct 41
through the toner receiving port 40a toward the toner discharge
port 40b.
[0039] As the replenishment motor M, a stepping motor capable of
managing a rotation speed or a blushless motor may be desirable.
However, when the blushless motor is used, it is required to detect
the rotation speed of the conveying screw 42 by an optical sensor
and an encoder.
[0040] The toner replenishment duct 43 extends downward in the
vertical direction from the toner discharge port 40b of the toner
conveying duct 41 and is communicated with the toner replenishment
port 37 of the developer container 30.
[0041] The shutter member 44 is horizontally slid between an
opening position where a lower end opening of the toner
replenishment duct 43 is opened and a closing position where the
opening is closed. In a state where the development device 3a is
not attached, the shutter member 44 is biased into the closing
position by a spring member. When the development device 3a is
attached, the shutter member 44 is pressed by the development
device 3a to be slid into the opening position against biasing
force of the spring member. Thereby, the opening of the toner
replenishment duct 43 is communicated with the toner replenishment
port 37 of the developer container 30.
[0042] When the toner concentration sensor 38 of the developer
container 30 of the development device 3a detects that an amount of
the toner in the developer container 30 is smaller than the
predetermined value, the conveying screw 42 is rotated to convey
the toner supplied from the toner container 4a toward the toner
discharge port 40b in the toner conveying duct 41. Then, the toner
is replenished to the developer container 30 from the toner
replenishment port 37 through the toner replenishment duct 43.
[0043] The image forming apparatus 100 includes a toner collection
device 50. The toner collection device 50 collects the toner
collected by the drum cleaning devices 7a to 7d and the belt
cleaning device 19.
[0044] Next, with reference to FIG. 4, the toner collection device
50 will be described. FIG. 4 is a perspective front view showing
the toner collection device 50.
[0045] The toner collection device 50 includes an intermediate
collection box 51 and a toner collection container 52. The
intermediate collection box 51 is disposed at the front side of the
image forming parts Pa to Pd and stores the collected toner
temporarily. The toner collection container 52 is disposed under
the intermediate collection box 51 and collects the toner
finally.
[0046] The intermediate collection box 51 has a hollow space having
a size corresponding to the four image forming parts Pa to Pd. The
intermediate collection box 51 has collected toner receiving ports
54 and a collected toner receiving port 55. The collected toner
receiving ports 54 are communicated with the discharge ports of the
drum cleaning devices 7a to 7d. The collected toner receiving port
55 is communicated with the toner discharge port of the belt
cleaning device 19. On a bottom portion of the intermediate
collection box 51, a conveying path 51a is formed along in the left
and right directions. The toner received from the collected toner
receiving ports 54 and 55 is fallen on the conveying path 51a by
its own weight. On one end of a bottom portion of the conveying
path 51a, a connection pipe 57 which is communicated with the toner
collection container 52 is connected.
[0047] In the conveying path 51a, a conveying screw 59 is rotatably
supported. The conveying screw 59 conveys the fallen toner on the
conveying path 51a toward the connection pipe 57. The conveyed
toner is collected in the toner collection container 52 through the
connection pipe 57. The toner collection container 52 is provided
with a weight sensor 60.
[0048] The image forming apparatus 100 includes a control part 70
which controls operation of each of the image forming parts Pa to
Pd, the toner replenishment device 40, the toner collection device
50 and the others.
[0049] With reference to FIG. 5, the control part 70 will be
described. FIG. 5 is a block diagram showing the control part. The
control part 70 is constructed by a CPU, a ROM storing a control
program, a RAM used as a working region and the others.
[0050] The control part 70 has a predicted consumption calculation
part 71, a replenishment motor control part 72, a replenishment
amount calculation part 73, a collected amount calculation part 74
and a display part 75.
[0051] The predicted consumption calculation part 71 calculates an
amount (a predicted consumption Y) of the toner to be consumed,
based on the image data input from the image input device. For
example, pixels constituting the image data are divided into an
image part and a non-image part, and the amount of the toner to be
consumed is calculated based on a number of the pixels constituting
the image part.
[0052] To the replenishment motor control part 72, an output value
output from the toner concentration sensor 38 of the developer
container 30 is input. Based on the input toner concentration, the
replenishment motor control part 72 controls the rotation speed of
the replenishment motor M which rotates the conveying screw 42 of
the toner replenishment device 40.
[0053] The replenishment amount calculation part 73 calculates the
rotation speed of the replenishment motor M, in which the rotation
speed is controlled by the replenishment motor control part 72.
Then, the replenishment amount calculation part 73 calculates the
rotation speed of the conveying screw 42 based on the rotation
speed of the replenishment motor M, and then an amount (a
replenishment amount X) of the toner replenished to each of the
development devices 3a to 3d from the corresponding toner
containers 4a to 4d is calculated based on the calculated rotation
speed of the conveying screw 42.
[0054] To the collected amount calculation part 74, an output value
output from the weight sensor 60 of the toner collection container
52 is input. The collected amount calculation part 74 calculates an
amount (a collected amount Z) of the toner collected in the toner
collection container 52 by the drum cleaning devices 7a to 7d and
the belt cleaning device 19.
[0055] The display part 75 is a liquid crystal panel provided on
the image forming apparatus 100 or a remote communication terminal
owned by a service man, for example.
[0056] An abnormality detecting process of a first embodiment in
the image forming apparatus 100 having the above described
configuration will be described with reference to a flowchart
showing in FIG. 6. In the abnormality detecting process, by
comparing the replenishment amount (X) of the toner replenished by
one toner replenishment performed by the toner replenishment device
40 with the predicted consumption (Y) of the toner to be consumed
by the image forming operation performed after the toner
replenishment, it is decided whether the replenished toner is
adequately consumed for the image forming operation or not is
decided.
[0057] First, at step S1, the replenishment motor control part 72
controls the replenishment motor M of the toner replenishment
device 40 to rotate the conveying screw 59 at a predetermined
rotation speed. Thereby, the toner is replenished to the developer
container 30 from the toner container 4a.
[0058] Next, at step S2, the replenishment motor control part 72
decides whether a toner concentration detected by the toner
concentration sensor 38 of the developer container 30 is equal to
or larger than a predetermined concentration Td or not.
[0059] As a result, when it is decided that the detected toner
concentration is equal to or larger than the predetermined
concentration Td, the process proceeds to step S3. At step S3, the
replenishment amount calculation part 73 calculates an amount X (a
replenishment amount) of the replenished toner from the rotation
speed of the conveying screw 59 in the toner replenishment. When it
is decided that the detected toner concentration is smaller than
the predetermined concentration Td, the process returns to step S1
and the toner replenishment is repeated until the detected toner
concentration is equal to or larger than the predetermined toner
concentration Td.
[0060] Next, when the image data is input from the image input
device at step S4, the predicted consumption calculation part 71
calculates a predicted consumption Y based on the input image data.
The predicted consumption Y calculated at step S5 is obtained by
adding a predicted consumption Y calculated from the image data
input at this time to a predicted consumption Y calculated from the
image data input at last time. That is, the predicted consumption Y
calculated at step S5 is obtained by accumulating the predicted
consumption Y predicted from the image data input after the toner
of the replenishment amount X is replenished. Then, after the image
forming operation is performed at step S6, the process proceeds to
step S7.
[0061] At step S7, the control part 70 decides whether an absolute
value (|X-Y|) of a difference (X-Y) of the replenishment amount X
and the predicted consumption Y is equal to or smaller than a
threshold value T1.
[0062] As a result, when it is decided that the absolute value
(|X-Y|) of the difference (X-Y) is equal to or smaller than the
threshold value T1, it is judged that an amount of the toner
contained in the developer container 30 is within a normal range
and an abnormality is not occurred. On the other hand, when it is
decided that the absolute value (|X-Y|) of the difference (X-Y) is
larger than the threshold value T1, it is judged that an
abnormality, such as an excessive or insufficient replenishment of
the toner, is occurred, and then the process proceeds to step
S8.
[0063] At step S8, the display part 75 informs a user of the
occurrence of the abnormality. When the abnormality is displayed on
the display part 75, a refresh operation in which the developer
carried on the developer carrier is once discharged is performed.
Alternatively, a maintenance work is performed by the service
man.
[0064] When the difference (X-Y) is positive (X-Y>0, X>Y),
that is, the replenishment amount X is larger than the predicted
consumption Y, because an amount of the toner contained in the
developer container 30 is excessive, a charging failure of the
toner is easily occurred. Alternatively, the replenished toner is
easily stayed in the developer container 30 without consumed
normally for the toner image formation. Therefore, some problems,
such as scattering of the toner in an inside of the image forming
apparatus 100 or fogging on the blank part, may be occurred. These
problems also occur owing to use of the image forming apparatus 100
in non-regular environment, such as continuous paper printing of a
high density image, continuous paper printing of a low density
image, leaving the image forming apparatus 100 for a long period,
high humidity environment, use of the developer of different
destination place, use of the non-regular developer and the others.
Alternatively, an insufficient amount of electric charge of the
toner causes the problems. On the other hand, when the difference
(X-Y) is negative (X-Y<0, X<Y), that is, the predicted
consumption Y is larger than the replenishment amount X, a
sufficient amount of the toner required for the normal toner image
formation is not replenished to the developer container 30.
[0065] Then, when the absolute value (|X-Y|) of the difference
(X-Y) is equal to or smaller than the threshold value T1 at step
S7, the process proceeds to step S9 and it is decided whether the
difference (X-Y) is positive or negative.
[0066] As a result, when it id decided that the difference (X-Y) is
positive (or 0), the process returns to step S2. After that, the
value of the replenishment amount X is continuously referred at
step S3.
[0067] On the other hand, when it is decided that the difference
(X-Y) is negative at step S9, the process returns to step S1 and
the replenishment of the toner is performed. That is, as described
above, when the difference (X-Y) is negative, because a sufficient
amount of the toner required for the normal image formation is not
replenished, the control part 70 controls so as to replenish the
toner. After that, at step S3, the value of the replenishment
amount X is obtained by adding the replenishment amount by the
replenishment at this time to the replenishment amount by the
replenishment at last time.
[0068] In this way, by using the replenishment amount (X) and the
predicted consumption (Y) during a period from the toner
replenishment at last time (the last-time replenishment) to the
toner replenishment at this time (the this-time replenishment) by
the toner replenishment device 40, it is decided whether the
replenished toner is adequately consumed for the image forming
operation or not.
[0069] As described above, according to the image forming apparatus
100 of the present disclosure, by using the predicted consumption Y
calculated from the image data and the replenishment amount X
calculated from the rotation speed of the replenishment motor M, an
abnormality of the image forming apparatus 100, such as the toner
scattering and the image density failure, can be informed. In this
way, because it is not required to use an optical sensor, it
becomes possible to inform a user of the abnormality immediately
and inexpensively. In addition, by deciding whether the difference
(X-Y) of the replenishment amount X and the predicted consumption Y
is positive or negative, an adequate countermeasure can be taken
before a remarkable abnormality is occurred. Accordingly, the
occurrence of the abnormality can be prevented previously and a
number of information of the abnormality can be decreased.
[0070] Next, an abnormality detecting process of a second
embodiment will be described with reference to a flowchart showing
in FIG. 7. In the abnormality detecting process, by comparing the
replenishment amount (X) of the toner replenished by one toner
replenishment of the toner replenishment device 40 with a sum of
the predicted consumption (Y) of the toner to be consumed by the
image forming operation performed after the toner replenishment and
the collected amount (Z) of the toner collected by the image
forming operation performed after the toner replenishment, it is
decided whether the replenished toner is adequately consumed for
the normal image formation or not.
[0071] First, at step S21, the replenishment motor control part 72
controls the toner replenishment device 40 to replenish the toner
to the developer container 30 from the toner container 4a.
[0072] Next, at step S22, the replenishment motor control part 72
decides whether a toner concentration detected by the toner
concentration sensor 38 of the developer container 30 is equal to
or larger than the predetermined concentration Td or not.
[0073] As a result, when it is decided that the detected toner
concentration is equal to or larger than the predetermined
concentration Td, the process proceeds to step S23. At step S23,
the replenishment amount calculation part 73 calculates an amount X
(a replenishment amount) of the replenished toner.
[0074] Next, when the image data is input from the image input
device at step S24, the predicted consumption calculation part 71
calculates a predicted consumption Y based on the input image data
at step S25. Then, after the image forming operation is performed
at step S26, the process proceeds to step S27.
[0075] At step S27, the collected amount calculation part 74
calculates an amount Z (a collected amount) of the toner collected
by the drum cleaning devices 7a to 7d and the belt cleaning device
19 in the image forming operation, and then the process proceeds to
step S28.
[0076] At step S28, the control part 70 decides whether an absolute
value (|X-(Y+Z)|) of a difference (X-(Y+Z)) of the replenishment
amount X and a sum of the predicted consumption Y and the collected
amount Z is equal to or smaller than a threshold value T2. The
threshold value T2 is smaller than the threshold value T1.
[0077] As a result, when it is decided that the absolute value
(|X-(Y+Z)|) of the difference (X-(Y+Z)) is equal to or smaller than
the threshold value T2, it is judged that an amount of the toner
contained in the developer container 30 is within a normal range
and an abnormality is not occurred. Then, the process proceeds to
step S30. At step S30, the same process as step S9 of the flowchart
(refer to FIG. 6) of the first embodiment is performed.
[0078] On the other hand, when it is decided that the absolute
value (|X-(Y+Z)|) of the difference (X-(Y+Z)) is larger than the
threshold value T2, it is judged that an abnormality, such as an
excessive or insufficient replenishment of the toner, is occurred,
and then the process proceeds to step S29.
[0079] At step S29, the display part 75 informs a user of the
occurrence of the abnormality. When the abnormality is displayed on
the display part 75, a refresh operation in which the developer
carried on the developer carrier is once discharged is performed.
Alternatively, a maintenance work is performed by the service
man.
[0080] In the second embodiment, the predicted consumption Y is
obtained by accumulating the predicted consumption Y predicted from
the image data input after the toner of the replenishment amount X
is replenished. The collected toner amount Z is obtained by
accumulating the collected toner amount Z collected in the image
forming operation performed after the toner of the replenishment
amount X is replenished.
[0081] According to the second embodiment, because an amount (the
collected amount Z) of the toner collected by the drum cleaning
devices 7a to 7d and the belt cleaning device 19 is used as an
amount to be consumed necessarily, an amount of the toner consumed
actually in the image forming operation can be calculated with a
small error. Accordingly, the second embodiment is preferred in
view of accurate information of the abnormality.
[0082] Next, an abnormality detecting process of a third embodiment
will be described with reference to a flowchart showing in FIG.
8.
[0083] Steps from step S31 to step S37 are the same as steps from
step S1 to step S7 of the first embodiment (refer to FIG. 6), and
their explanation is omitted. In the third embodiment, when the
absolute value (|X-Y|) of the difference (X-Y) is larger than the
threshold value T1 at step S37, the process proceeds to step S38,
and it is decided whether the difference (X-Y) is positive or
negative.
[0084] As a result, when it is decided whether the difference (X-Y)
is positive (or 0), the process returns to step S32 in the same way
as the first embodiment. On the other hand, when it is decided
whether the difference (X-Y) is negative, the process proceeds to
step S39.
[0085] At step S39, it is decided whether a number of times that it
is decided that the absolute value (|X-Y|) of the difference (X-Y)
is larger than the threshold value T1 at step S37 is a
predetermined number of time N or not. For example, N may be
two.
[0086] As a result, when it is judged that the number of times is
smaller than N, the process returns to step S31, and the
replenishment of the toner is performed. On the other hand, it is
decided whether the number of times that it is decided that
absolute value (|X-Y|) of the difference (X-Y) is larger than the
threshold value T1 at step S37 is N, the process proceeds to step
S40, and the abnormality is informed in the same way as step S8 of
the first embodiment.
[0087] In the third embodiment, when it is decided that the
absolute value (|X-Y|) of the difference (X-Y) is equal to or
smaller than the threshold value T1, a countermeasure is not taken.
However, when it is decided that the absolute value (|X-Y|) of the
difference (X-Y) is larger than the threshold value T1, a
countermeasure for preventing enlarging of the abnormality is
immediately taken before the abnormality is informed. Then, the
abnormality is informed before the abnormality becomes remarkable.
Accordingly, a number of the information of the abnormality can be
decreased.
[0088] In an preferable example of the above embodiments, the
predicted consumption calculation part 71 is configured to divide
the image part of the image data into a solid pattern and a line
pattern and to make the predicted consumption different for each
pattern. A document having a plurality of the solid patterns is a
photograph, for example. Because an edge portion of the
electrostatic latent image formed on each of the photosensitive
drums 1a to 1d has high electric field, a more amount of the toner
is adhered to the edge portion than the other portion. Because the
line pattern contains a larger number of the edge portions than the
solid pattern, an adhered toner amount per unit area is larger in
the line pattern than in the solid pattern. Then, it is set that
the line pattern consumes the toner larger than the solid pattern
by a predetermined amount. Thereby, it becomes possible to
accurately predict the consumption (the predicted consumption Y)
from the image data and to accurately inform a user of the
abnormality.
[0089] In addition, the replenishment amount X may be calculated by
measuring a concentration of the magnetic developer in the
developer containers 30 of the development devise 3a to 3d using a
magnetic permeability sensor. Furthermore, the collected amount Z
may be calculated by using a floating type sensor, instead of the
weight sensor 60.
[0090] In addition, an optical sensor may be provided so as to
detect a density of a blank part of the photosensitive drums 1a to
1d and the intermediate transferring belt 8. In this case, when the
above described abnormality is informed, the optical sensor detects
the blank part and then it is decided whether the fogging is
occurred on the blank part based on the detection result or not.
When it is decided that the fogging is occurred, it is judged that
the abnormality is caused by the fogging on the blank part. On the
other hand, when it is decided that the fogging is not occurred, it
is judged that the abnormality is caused by the toner scattering or
the excessive concentration of the toner. By judging the cause of
the abnormality as described above, an adequate countermeasure
corresponding to the cause can be immediately taken.
[0091] In addition, the control part may observe a transition of
the difference (X-Y) of the replenishment amount X and the
predicted consumption Y, predict a time when the difference (X-Y)
reaches the threshold value and then perform the toner refresh
operation or the maintenance work by a service man before the
difference (X-Y) reaches the threshold value. Furthermore, by
considering temperature of the image forming apparatus 100,
humidity, printing rate, toner cartridge information, concentration
calibration information or the others, more accurate prediction of
the abnormality and analyze of the cause of the abnormality can
become possible.
[0092] The embodiments were described in a case of applying the
configuration of the present disclosure to the color printer. On
the other hand, in another embodiment, the configuration of the
disclosure may be applied to another image forming apparatus, such
as a copying machine, a facsimile or a multifunction peripheral,
except for the color printer.
[0093] While the preferable embodiment and its modified example of
the image forming apparatus of the present disclosure have been
described above and various technically preferable configurations
have been illustrated, a technical range of the disclosure is not
to be restricted by the description and illustration of the
embodiment. Further, the components in the embodiment of the
disclosure may be suitably replaced with other components, or
variously combined with the other components. The claims are not
restricted by the description of the embodiment of the disclosure
as mentioned above.
* * * * *